Avoid importing unix local sandboxes on Windows

Author: akshitnanda

src/agents/sandbox/sandboxes/__init__.py

@@ -5,12 +5,20 @@
 execution environments (e.g. Docker, local Unix).
 """
 
-from .unix_local import (
-    UnixLocalSandboxClient,
-    UnixLocalSandboxClientOptions,
-    UnixLocalSandboxSession,
-    UnixLocalSandboxSessionState,
-)
+import sys
+
+_HAS_UNIX_LOCAL = False
+
+if sys.platform != "win32":
+    # The Unix local backend depends on Unix-only stdlib modules like fcntl and termios.
+    from .unix_local import (
+        UnixLocalSandboxClient,
+        UnixLocalSandboxClientOptions,
+        UnixLocalSandboxSession,
+        UnixLocalSandboxSessionState,
+    )
+
+    _HAS_UNIX_LOCAL = True
 
 try:
     from .docker import (  # noqa: F401
@@ -25,12 +33,17 @@
     # Docker is an optional extra; keep base imports working without it.
     _HAS_DOCKER = False
 
-__all__ = [
-    "UnixLocalSandboxClient",
-    "UnixLocalSandboxClientOptions",
-    "UnixLocalSandboxSession",
-    "UnixLocalSandboxSessionState",
-]
+__all__: list[str] = []
+
+if _HAS_UNIX_LOCAL:
+    __all__.extend(
+        [
+            "UnixLocalSandboxClient",
+            "UnixLocalSandboxClientOptions",
+            "UnixLocalSandboxSession",
+            "UnixLocalSandboxSessionState",
+        ]
+    )
 
 if _HAS_DOCKER:
     __all__.extend(

tests/sandbox/test_sandboxes_import.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+import importlib
+import sys
+
+
+def test_sandboxes_package_import_skips_unix_local_on_windows(monkeypatch) -> None:
+    original_module = sys.modules.get("agents.sandbox.sandboxes")
+    sandbox_package = importlib.import_module("agents.sandbox")
+
+    monkeypatch.setattr(sys, "platform", "win32")
+    sys.modules.pop("agents.sandbox.sandboxes", None)
+
+    try:
+        sandboxes = importlib.import_module("agents.sandbox.sandboxes")
+        assert sandboxes.__name__ == "agents.sandbox.sandboxes"
+        assert "UnixLocalSandboxClient" not in sandboxes.__all__
+        assert not hasattr(sandboxes, "UnixLocalSandboxClient")
+    finally:
+        sys.modules.pop("agents.sandbox.sandboxes", None)
+        if original_module is not None:
+            sys.modules["agents.sandbox.sandboxes"] = original_module
+            setattr(sandbox_package, "sandboxes", original_module)
+        else:
+            try:
+                delattr(sandbox_package, "sandboxes")
+            except AttributeError:
+                pass